Japanese to English Medical Medical (general)

My question is regarding the term '秤量値別'. Could this be translated as 'donation volume', given that the incidence of side effects in male blood donors (男性全献血者の秤量値別発現率) is being analyzed? I keep coming across the term transated as 'weight', but to use 'weight' would be confusing because 'body'weight' is also included in the analysis.

More specifically, in the study blood donation is divided into whole blood and apheresis donation, i.e. platelet apheresis and plasma apheresis.

Thanks for your help.